Mechanism of OH radical-induced oxidation of p-cresol to p-methylphenoxyl radical

Mechanism of OH radical-induced oxidation of p-cresol to p-methylphenoxyl radical
Wojnárovits, L.; Földiák, G.; D'Angelantonio, M.; Emmi, S.
2004-10-13 00:00:00
The OH radical-induced oxidation of p-cresol to p-methylphenoxyl radical was studied in aqueous solution in a wide pH range by means of pulse radiolysis combined with optical spectroscopy. OH-adduct cyclohexadienyl type radicals were identified as intermediates of the reaction. In the acidic pH range the first-order rate coefficient of phenoxyl radical formation was found linearly dependent on the H3O+ concentration yielding a bimolecular rate coefficient of 1.8 × 108 mol–1 dm3 s–1. In the alkaline range a linear dependence was found on the OH– concentration with rate coefficient of 4.9 × 1010 mol–1 dm3 s–1. These findings were interpreted in terms of acid-base catalysis of the H2O elimination from the OH-adduct. With the time resolution applied, 30 ns, the radical cation p-CH3C6H4OH+. was not observed as intermediate.
http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.pngResearch on Chemical IntermediatesSpringer Journalshttp://www.deepdyve.com/lp/springer-journals/mechanism-of-oh-radical-induced-oxidation-of-p-cresol-to-p-FUp00q05Mf

Mechanism of OH radical-induced oxidation of p-cresol to p-methylphenoxyl radical

Abstract

The OH radical-induced oxidation of p-cresol to p-methylphenoxyl radical was studied in aqueous solution in a wide pH range by means of pulse radiolysis combined with optical spectroscopy. OH-adduct cyclohexadienyl type radicals were identified as intermediates of the reaction. In the acidic pH range the first-order rate coefficient of phenoxyl radical formation was found linearly dependent on the H3O+ concentration yielding a bimolecular rate coefficient of 1.8 × 108 mol–1 dm3 s–1. In the alkaline range a linear dependence was found on the OH– concentration with rate coefficient of 4.9 × 1010 mol–1 dm3 s–1. These findings were interpreted in terms of acid-base catalysis of the H2O elimination from the OH-adduct. With the time resolution applied, 30 ns, the radical cation p-CH3C6H4OH+. was not observed as intermediate.

Journal

Research on Chemical Intermediates
– Springer Journals

Published: Oct 13, 2004

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References

The Study of Fast Processes and Transient Species by Electron Pulse Radiolysis